Lieutenant Governor Timothy P. Murray was driving 100 miles per hour, without a seat belt, possibly because he had fallen asleep behind the wheel in the moments before he totaled his state-owned car, according to a Massachusetts State Police investigation of the car’s “black box” data released today.

The circumstances of the crash, and the tangled wreckage of the car, make it all the more remarkable that Murray emerged physically unscathed from the rollover.

Murray will be ticketed $555 for the Nov. 2 car accident, but will not face more significant charges.

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Murray said in a statement that he accepted the black box data and took full responsibility for the accident.

“I understand that the vehicle accelerated rapidly without braking or turning in the seconds before the accident. The State Police have said that this is consistent with what happens when someone falls asleep at the wheel and I believe that is what caused my accident,” Murray said.

“I appreciate the response and the work of the State Police and I am especially thankful for all of the good wishes my family and I have received since the accident,” he said.

The investigation showed Murray was driving 75 miles per hour in the seconds leading up to the crash, which occurred before dawn on a stretch of Interstate 190 in Sterling. But his foot fell harder on the car’s accelerator, increasing his speed to 108 miles per hour as he slid off the roadway and into a rock ledge, flipping twice. His speed was recorded at 92 miles per hour upon impact with the ledge.

State Police had previously blamed the crash on black ice, but backtracked on that conclusion after examining the black box data.

“Based on this data, it is not possible to conclude with 100 percent certainty the cause of the crash,” said State Police spokesman David Procopio. “The data, however, is potentially consistent with an operator falling asleep and not realizing the car had gone off the road until the point of impact. Facts that are potentially indicative of this cause are the steady acceleration, shallow angle of exit from the roadway, and lack of braking and corrective steering.”

The posted speed limit in the area is 65 miles per hour, and the lieutenant governor had previously said that he had not been speeding and that he had been wearing a seat belt.

Murray has not been charged with reckless driving, something a state official attributed to the lack of injuries resulting from the crash.

The data also show he was traveling for about 40 minutes, which appeared to be consistent with his version of the story.

Murray had previously said that on the morning of the accident he left his house in Worcester before 5 a.m., because he was awake and did not want to disturb his wife and two daughters. He has said he then drove about 30 miles—in complete darkness—to survey damage from an early snowstorm and to buy coffee and newspapers. Following the crash, he asked for, and passed, a sobriety test.

State Police had earlier denied media requests to retrieve the black box data, saying its investigators had more urgent cases and that the cause of Murray’s crash had already been attributed to icy roads.

But the police reversed the decision after Murray, under continuing pressure, asked for its release.

Both the Globe and the Boston Herald had requested the black box data, with the Herald filing an appeal with Secretary of State William F. Galvin. Galvin’s office then requested the information be made public.

Murray, 43, was assigned the unmarked, 2007 Ford Crown Victoria to use for state business. Both Murray and Governor Deval Patrick are supplied full-time State Police drivers, but they also, on occasion, drive themselves for errands. Murray’s crash occurred about two hours before his trooper was scheduled to pick him up for the day’s activities.

Like many recent-model cars, state cruisers are equipped with black box-like devices that capture data such as speed, throttle position, and brake deployment.

The vehicle was purchased for about $35,000 and valued at $9,000 at the time of the crash.